Crimping apparatus



3,526,937 CRIMPING APPARATUS Hermann Kubler, Remscheid-Lennep, Germany, assignor to Barmag Barmer Maschinenfabrik Aktiengesellschaft, Wuppertal, Germany Filed Apr. 21, 1967, Ser. No. 632,623 Claims priority, applicltigl 8(grmany, Apr. 29, 1966,

Inf. c1. Ding 1/12 U.S. Cl. 281.6 5 Claims ABSTRACT F THE DISCLOSURE This invention relates to a crimping apparatus, and more particularly, to a device and process wherein a melt-spun synthetic yarn after being stretched and while traveling at high speed can be inserted into a compression chamber of special design and crimped or textured therein, after which the crimped yarn can be taken oli or spooled and/or fixed in a conventional manner, all steps being carried out in a continuous sequence without intermittent yarn spooling or storage.

The production of a crimped yarn by means of a compression chamber or stuffing box is well known. A yarn in which the filaments have been previously stretched is drawn from a storage spool or initial feed roll and transported into one end of the compression chamber by a pair of positivelydriven feed rolls. At or near its opposite end, this chamber is narrowed or closed by a counterpressure element such as a lid, clapper, stop, piston or the like for the purpose of collecting the yarn in the chamber and compressing it into a large number of bends or arcs. The yarn is compressed in the chamber until the pressure exerted by the yarn is suicient to at least partly open the lid or lift the piston and discharge the yarn. All known processes for the compression crimping of yarn operate according to this principle.

In these known processes, it is a general practice to separate the stretching of the melt-spun yarn as one process from the crimping under compression as a disvUnited States Patent O tinct non-sequential step, i.e. to first store the stretched yarn on a spool or the like and only then supplying the yarn from this storage spoolto the crimping operation. However, this discontinuous procedure is very time-consuming and expensive because of the extra equipment required to temporarily spool and store the stretched On the other hand, it is quite difficult to combine the melt-spinning, stretching and crimping steps into one continuous sequential procedure because this would normally require very special precautions in view of the extremely high linear speed of the yarn being processed. During stretching or drawing of the filaments in the yarn, each filament is stretched to a multiple of its original length and the yarn or thread likewise increases in length with a corresponding increase in its linear speed as it is transferred to the next operation. The yarn emerging with such a high speed after stretching must be inserted in the compression device or crimper when the entire sequence of operations is initially started, and this is not possible with conventional compression crimping devices.

The primary object of the present invention is to pro- Patented Sept. 8, 1970 ICC vide a novel compression crimping apparatus whereby the melt-spun and stretched yarn of a thermoplastic polymer can be conducted in a sequentially continuous operation into a crimping chamber without providing any intermediate spooling or storage of the crimped yarn.

Another object of the invention is to provide a crimping apparatus capable of receiving the initially spun and stretched yarn at a high rate of linear yarn speed and then being quickly activated to begin the crimping operation.

Still another object of the invention is to provide a crimping device in which heat developed in the yarn during stretching can be utilized for fixing the crimped yarn.

These and other objects and advantages of the invention will become more apparent upon careful consideration of the following detailed disclosure.

In accordance with the present invention, it has now been found that one can produce a crimped yarn from a synthetic thermoplastic liber-forming polymer in a series of sequentially continuous steps which include melt-spinning ilaments of the polymer and stretching them for molecular orientation into a fibrous yarn in a continuous operating sequence with the linear speed of the spun yarn being substantially increased at the point of stretching, leading this initially spun and stretched yarn from this point of stretching at said increased linear speed through an elongated compression chamber opened along one side, this chamber -when closed temporarily collecting a length of yarn and imparting a crimping effect thereto, then immediately closing the open side of the compression chamber for collecting and crimping the yarn, and finally withdrawing crimped yarn from the chamber at a rate commensurate with its introduction therein corresponding to its linear speed after stretching. By introducing the yarn into the compression chamber directly after stretching, the heat developed by the yarn during the stretching or drawing process can be advantageously used as an aid to fix the desired deformation of iilaments during crimping. However, it is also feasible to heat the yarn in an intermediate step between stretching and crimping while still maintaining the high linear speed of the yarn.

The novel compression or crimping apparatus of the invention is primarily characterized by its construction as an elongated chamber having one side wall in the form of a door which can be readily opened for rapid and easy insertion of the stretched yarn in spite of its rapid linear speed and which ca u then be closed quickly and securely to carry out the desired crimping of the yarn.

In other respects, the elongated compression chamber is `provided rwith conventional elements and associated structure including the usual closure means within and/or extending across the chamber for restriction of the longitudinal passage of yarn therethrough, and also feed rollers adjacent the yarn inlet end of the chamber to continuously vdeliver the yarn into the chamber. However, it is particuquence of continuous operating steps according to the invention;

FIG. 2 is a similar schematic flow sheet illustrating alternative embodiments of the novel process;

FIG. 3 is a perspective view of a preferred embodiment l of the crimping apparatus of the invention in which the movable door is in an open position to receive the freshly spun and stretched yarn;

FIG. 4 is a partial cross-sectional view of the compression chamber with the type of closure member shown in FIG. 3 after the door has been closed;

FIG. 5 is a partial cross-sectional View of another compression chamber for the purpose of illustrating the use of two closure members providing separate sequential compression zones;

FIG. 6 is a partial cross-sectional view taken on line 6-6 of FIG. 3 after the door of the compression charnber is moved to its closed position, this portion being illustrated representing a preferred use of an electromagnet to hold the door in its closed position and the switching means employed for actuating and deactuating the electromagnet.

Referring first to FIGS. 3 and 4, the spun and stretched yarn 10 is located in the compression chamber which is in the form of an elongated tube or channel formed by the back wall 12, the opposite side walls 13 and 14 and the door 15. In a recessed or partly removed section of this door 15, the compression lid or closure plate 16 is mounted with its axis of rotation or fulcrum point located within the door, e.g. as indicated in FIG. 4. This closure plate 16 carries or is integrally joined with an outwardly extending lever arm 11 which can be loaded with weights 17 so as to exert any required load or yielding counterpressure upon the length of yarn as it collects in the closed compression chamber. The pivotal depth or extent of closure of the compression plate 16 can be adjusted by means of the setscrew 18.

The door is mounted for rotation on the hinge 19 and is maintained in its closed position against the outer faces of side members 13 and 14 by means of an electromagnet 20. For this purpose, the door can be constructed entirely of iron or a similar magnetizable material or else a magnetizable plate can be mounted on the door directly opposite the electromagnet. When opening the door 15, the electromagnet 20 is turned off by switch 22 which in turn is actuated by the door handle 21.

When actually inserting the freshly spun and stretched thread or yarn 10 into the compression chamber, the door 15 is in its open position, the yarn is placed into a suitable notch or slot in `guide member 23 and positioned across the length of the compression plate 16, and the door is then slammed shut forcing the thread between the feed rollers 24 and 25. Since the electromagnet 20 is turned on when the handle depresses the switch 22, the door 15 remains securely closed.

The operation of the electromagnet in response to closing and opening the door is more completely illustrated in FIG. 6. The shaft of the handle 21 is rotatably mounted in the door 15 or in an attached plate and is urged in a counter-clockwise direction by the spring 28 until it reaches a stop 29, the clockwise rotation of the handle also being limited by a second stop 30, both stops fitting into a suitable circumferentially recessed slot extending partly around the handle shaft. The inner end of the handle shaft provides a cammed projection 31 which contacts the switch 22 and pushes it inwardly against the resilient opposing force of the switch spring 32 closing the electromagnet contact member 33 when the door 15 is closed and the handle 21 is in its normal counter-clockwise position.

In order to deactuate the electromagnet 20, the handle 21 is simply turned in a clockwise direction so that the switch 22 rides outwardly on the cam surface 31, thereby opening the contact 33. The handle and switch are readily constructed so that only a quarter turn or less on the handle will deactivate the electromagnet, permitting the door 15 to be swung to its open position.

As shown in FIG. 5, the compression chamber can also be constructed to provide two compression spaces or crimping zones separated from one another by mounting two compression plates 26 and 27 in the movable door 15.

All of the essential elements as well as other associated structure can be easily attached to a framework or housing 34, e.g. which may also contain any suitable drive means for the feed rolls 24 and 25. In addition, one can use conventional take-up spools and/ or suitable means for fixing the crimp in the yarn in direct combination with the particular crimping device of the invention. Since these portions of the overall apparatus require no special modification, they are merely illustrated in schematic form in the flow diagrams of FIGS. 1 and 2.

Referring briefly to these flow diagrams, any suitable fiber-forming polymer is melt-spun out of the spinning nozzle 1, conducted through a conventional stretching device 2, crimped by the device illustrated herein at 4 and then fixed in a subsequent operation 5, as shown in FIG. l. Alternatively, in the case of the process shown in FIG. 2, the yarn emerges from the spinning nozzle 1, is stretched for molecular orientation at 2, further heated at 3, compressed in the crimping device 4 and then optionally spooled at 6 or taken off and fixed at 5.

Suitable polymers capable of being melt-spun and stretched into a fibrous yarn include polyamides such as nylon, polyesters such as polyethylene terephthalate, acrylonitrile, and other well-known fiber-forming thermoplastic polymers. In stretching or drawing the thread, filaments or yarn after its initial spinning from the melt, it is a common practice to extend the length a multiple of the spun length, e.g. from 2 to 5 times the spun length. As a result, the linear speed of the yarn after stretching increases correspondingly. With the particular crimping device of the present invention, it is possible to handle the yarn at these high yarn speeds, e.g. of at least about 1500 meters/minute and usually 2000 meters/minute or more, such that the initially spun and stretched yarn can be introduced and passed through the compression chamber and feed rolls in a rapid and secure manner.

In subjecting the yarn to crimping it is often desirable to heat the yarn by exposing it to hot air or steam before and/or after crimping either to facilitate the crimping operation or to fix the crimped yarn. These conventional heating steps are likewise useful in the process of the present invention, but the crimping apparatus and process of this invention does offer the added advantage of rapidly introducing the stretched threads into the compression chamber for utilization of heat developed solely by the stretching itself.

The action of the compression plate or similar closure means in the crimping zone of the compression chamber is well known in this art, and it will be recognized that a substantial length of thread or yarn is packed or collected above the compression plate in normal continuous opera.- tion. FIGS. 4 and 5 merely illustrate the initial stage of this yarn collection immediately after the door has been closed.

Once the thread or yarn has collected or built up to a predetermined level as adjusted by the counterweights on the compression plate, it is then necessary of course to withdraw the yarn at a rate approximately equal to its linear speed after stretching. This does not mean that the yarn emerges from the compression chamber at the same linear speed as that which occurs after stretching, since it may in fact emergen more slowly as a relatively large bundle, or it may also require a more rapid linear speed where drawn tautly before it emerges from the compression chamber due to the shortening effect which crimping has on the overall length of yarn. This rate of withdrawal therefore refers to the equilibrium which will exist during most of the continuous process between the Weight or volume of yarn being introduced into the compression chamber and the 'weight or volume of yarn being discharged from this chamber. When starting up the apparatus for the initial collection of yarn or when closing the apparatus down, there will naturally be an imbalance in the input and output weights or volumes of yam, but this is of relatively short duration.

In using the crimping apparatus and process of the invention, it has been rfound applicable to a variety of synthetie yarns over a wide range of stretching conditions and linear speeds after stretching, e.g. from 2,000 to 3,000 meters/minute. Since it Was not previously possible to handle yarns at these speeds except by temporarily winding and storing the stretched yarn, the present invention offers a substantial economic saving and simpliiication in that all of the steps from melt spinning through crimping can be carried out in a continuous sequence. Other conventional steps and apparatus aside from the crimping device need not be altered and the nal product in the form of a spooled and/or fixed crimped yarn requires no additional treatment. The yarn product is of course identical in its crimped properties and quality to yarns in which the same steps are carried out in a discontinuous manner. l

The invention is hereby claimed as follows:

1. An apparatus for crimping synthetic yarn comprising:

an elongated compression chamber having one side wall thereof formed by a movable door pivotallyy hinged along one edge and arranged to open and close said chamber for insertion of a length of yarn therein; means to hold said door in a closed position;

feed rollers arranged adjacent an open inlet end of said compression chamber to deliver said yarn into the chamber;

means mounted on said door to receive said yarn 'when said door is in the open position and to guide said yarn into said feed rollers when said door is in the closed position; and

yielding closure means extending across said chamber to restrict the longitudinal passage of yarn therethrough and to place said yarn under compression for crimping.

2. An apparatus as claimed in claim 1 wherein said door contains said yielding closure means.

3. An apparatus as claimed in claim 2 including an electromagnet mounted to magnetically hold said door in its closed position, a handle in said door, switch means operated by the handle in said door to actuate said electromagnet responsive to the closing of said door and to deactuate said electromagnet responsive to turning of said handle.

4. An apparatus as claimed in claim 1 wherein said elongated compression chamber is divided into two compression zones by two yielding closure means.

5. An apparatus as claimed in claim 1 wherein said means to hold said door in a closed position includes an electromagnet, switch means to actuate said electromagnet responsive to the closing of said door, and means to move said switch to an oif position deactuating said electromagnet.

References Cited UNITED STATES PATENTS 2,820,988 1/ 1958 Wegener. 2,914,835 12/ 1959 Slayter et al. 3,022,545 2/1962 Wylde et al. 3,134,833 5/1964 Ciporin et al. 3,199,281 8/ 1965 Maerov et al. 57-140` 3,271,943 9/ 1966 Williams 264-168 X 3,398,220 8/ 1968 Port et al. 264-282 X 3,398,223 8/ 1968 Schatz et al. 3,345,719 10/1967 Schatz et al. 2'8-1 3,157,847 2/ 1965 Gonsalves 28-l.4 3,241,213 3/ 1966 Thompson et al. 2'8-1.6 3,337,930 -8/1967 Aelion et al. 28-1.6 3,431,002 3/ 1969 Melgaard 292-2515 ROBERT R. MACKEY, Primary Examiner U.S. Cl. X.R.

22253@ UNITED STATES PATENT oFFICE' t CERTIFICATE OF CORRECTION Patent No. 3,526,937 Dated September' 8, 1970 Inventor(s) Hermann Kbler It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1I, line 62, "emergen" should read emerge Column 6, line 29, 3,157,81I7 should read 3,167,81I7

SKiN U SELLE DEC l 19m (SEAL) new Eamammewhmlrmm2. JR.

@mating Officer Gomssioner yor Patents 

